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v3.25.3

Consolidated Statements of Earnings (Parenthetical) | Sep. 30, 2025 | Sep. 30, 2024
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Income Statement [Abstract] |  |
Economic equivalent of Class B share to Class A share | 0.0667% | 0.0667%

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- Definition Economic equivalent of Class B share represented as a fraction of Class A share. + References No definition available. + Details
Name: | brka_EconomicEquivalentPercentageOfClassBCommonShareToClassACommonShare
Namespace Prefix: | brka_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

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- References No definition available. + Details
Name: | us-gaap_IncomeStatementAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration